1.1 Classification of optical glass types

According to the position and glass composition of refractive index (nd) and dispersion coefficient (υd) in nd-υd domain diagram, optical glass types are classified into the 17 groups shown in table 1.

Table 1

Group

Code

Group

Code

Fluor Crown

FK

Light Flint

QF

Light Crown

QK

Flint

F

Phosphate Crown

PK

Barium Flint

BaF

Crown

K

Dense Barium Flint

ZBaF

Barium Crown

BaK

Dense Flint

ZF

Dense Crown

ZK

Lanthanum Flint

LaF

Lanthanum Crown

LaK

Dense Lanthanum Flint

ZLaF

Crown Flint

KF

Titanium Flint

TiF

Special Flint

TF

1.2 Designation of optical glass types

Each optical glass type is designated by its glass group code and a number. In addition to our glass type designation, a six-digit code is used in this catalog. The first three digits indicate the first three numbers after the decimal point of nd while the last three digits represent the Abbe-number. For example, F4 with nd=1.62005 and υd=36.35 is indicated by its six-digit code 620-364.

1.3 Designation of environment-friendly glass types

Glass types which exclude lead, arsenic, cadmium and radioactive elements from their compositions are distinguished by the prefix, ＂H＂, for example, H-F4.

1.4 Designation of low softening point glass types

Low softening point glass types that are used for mould pressing are distinguished by the prefix ＂D＂, for example, D-ZK3.

1.5 Designation of high transmittance optical glass types

High transmittance optical glass types are distinguished by the postfix “HT”, for example, H-ZF52HT.